Vinyl chloride can be prepared using a number of well known processes. Two familiar processes are the hydrochlorination of acetylene and the oxychlorination of ethylene to form dichloroethane which in turn is dehydrohalogenated to form vinyl chloride, see U.S. Pat. No. 2,847,483. As acetylene is more expensive than ethylene, the latter process is economically favored and much activity is noted in this art area, see U.S. Pat. No's. 3,634,330; 3,454,663; 3,448,057; and 3,624,170. Ethylene, in turn, can be prepared by the oxydehydrogenation of ethane, see U.S. Pat. No. 3,769,362. In all processes, high yields of ethylene are particularly desired. In processes which use ethane as a feed stock in the presence of either chlorine or hydrogen chloride, they can produce not only ethylene but also can directly produce vinyl chloride and other valuable products such as ethylene dichloride, ethyl chloride, and the like. The ethylene, ethylene dichloride, and ethyl chloride can be readily reacted to form more vinyl chloride.
Preparation of vinyl chloride can be effected by the balanced vinyl chloride monomer (VCM) process, as described in the article entitled "Oxychlorination of Ethylene" by Messrs. Cowfer and Magistro in "Encyclopedia of Chem. Tech., 3rd Ed; Wiley; New York, 1983; Vol. 23, pp. 865-885. The balanced vinyl chloride monomer process is schematically illustrated in FIG. 1, herein.
In one proposed method in which ethylene is produced, ethane, a chlorine source and oxygen are passed through a reactor maintained at about 550.degree. C. where fluidized solid solution catalyst is used to produce a stream from the reactor containing ethylene, hydrogen chloride, vinyl chloride and water. The amount of vinyl chloride in this stream, also identified as Stream A in the drawings, was in the range of 7-25% on molar efficiency basis; that is, 7-25 moles of vinyl chloride were produced for every 100 moles of ethane which were fed to the reactor. Stream A was fed into a separator where vinyl chloride was separated from ethylene and other constituents. Ethylene and other constituents were fed into the oxychlorination unit of FIG. 1 and the ethylene dichloride product was treated and subsequently produced vinyl chloride monomer, as outlined in FIG. 1.
A proposed process of using a separator to separate vinyl chloride from ethylene and other constituents is schematically depicted in FIG. 2. It would be desirable to produce ethylene from ethane whereby the amount of vinyl chloride produced would be minimized so as to reduce or eliminate the separation step thus allowing the product stream containing ethylene to be fed directly to an oxychlorination process unit.